CDK2 and gastric cancer: In particular, cordycepin regulates the phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) signaling pathway and inhibits cyclin-dependent kinase 2 (Cdk-2), extracellular signal-regulated kinase 1/2 (ERK1/2) and Rb/E2F1 and fibroblast growth factor receptors 1–4 (FGFR 1–4) regulate the cell cycle and further reduce the growth of testicular tumors, gastric cancer cells and cervical cancer cells [25,26].